Iron Golf Club Head and Iron Golf Club

ABSTRACT

An iron golf club head includes a main body and a hosel. A face and the hosel are made from the same material. The face includes a thin portion and a thick portion having a larger thickness than the thin portion in a face-to-back direction. The thin portion has a larger area than the thick portion. The thick portion is located centrally of a back face in a toe-to-heel direction, surrounded by the thin portion, and protrudes from the thin portion in the face-to-back direction. The face has a hardness of HV510 or more and HV600 or less. The hosel has a hardness of HV300 or less.

CROSS REFERENCE TO RELATED APPLICATIONS

This nonprovisional application is based on Japanese Patent Application No. 2022-092525 filed on Jun. 7, 2022 with the Japan Patent Office, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an iron golf club head and an iron golf club.

Description of the Background Art

Japanese Patent No. 6706950 discloses an iron golf club head that can achieve both high rebound property and high durability. The iron golf club head disclosed in the above-identified patent publication includes a thick portion, a thin portion, and a tapered portion. The thick portion is located almost centrally in the direction from the toe side toward the heel side. The thin portion is located around the thick portion. The tapered portion is located between the thick portion and the thin portion.

The iron golf club heads are required to have an angle adjustment capability for adjusting the loft angle and the lie angle. The patent publication does not disclose the angle adjustment capability.

SUMMARY OF THE INVENTION

The present invention has been made in view of the problems as described above, and an object of the present invention is to provide an iron golf club head and an iron golf club that can achieve both high rebound property and high durability and improve the angle adjustment capability.

An iron golf club head of the present invention includes a main body and a hosel. The main body includes a toe, a heel, a face, and a back face. The hosel is connected to the heel of the main body. The face and the hosel are made from the same material. The face includes a thin portion and a thick portion having a larger thickness than the thin portion in a face-to-back direction from the face toward the back face. The thin portion has a larger area than the thick portion. The thick portion is located centrally of the back face in a toe-to-heel direction from the toe toward the heel, surrounded by the thin portion, and protrudes from the thin portion in the face-to-back direction. The face has a hardness of HV510 or more and HV600 or less. The hosel has a hardness of HV300 or less.

With the iron golf club head and the iron golf club of the present invention, both high rebound property and high durability can be achieved and the angle adjustment capability can be improved.

The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view schematically showing a configuration of an iron golf club head according to Embodiment 1.

FIG. 2 is a rear view schematically showing the configuration of the iron golf club head according to Embodiment 1.

FIG. 3 is a right side view schematically showing the configuration of the iron golf club head according to Embodiment 1.

FIG. 4 is a cross-sectional view along a line IV-IV in FIG. 3 .

FIG. 5 is a cross-sectional view along a line V-V in FIG. 2 .

FIG. 6 is a cross-sectional view along a line VI-VI in FIG. 2 .

FIG. 7 is a rear view schematically showing a configuration of an iron golf club according to Embodiment 1.

FIG. 8 is a rear view schematically showing a configuration of an iron golf club head according to Embodiment 2.

FIG. 9 is a front view schematically showing a configuration of an iron golf club head according to Embodiment 3.

FIG. 10 is a rear view schematically showing the configuration of the iron golf club head according to Embodiment 3.

FIG. 11 is a right side view schematically showing the configuration of the iron golf club head according to Embodiment 3.

FIG. 12 is a cross-sectional view along a line XII-XII in FIG. 11 .

FIG. 13 is a cross-sectional view along a line XIII-XIII in FIG. 10 .

FIG. 14 is a cross-sectional view along a line XIV-XIV in FIG. 10 .

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are hereinafter described based on the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference characters, and a description thereof is not herein repeated, unless otherwise specified.

Embodiment 1

Referring to FIGS. 1 to 6 , an iron golf club head 100 according to Embodiment 1 is described.

As shown in FIGS. 1 and 2 , iron golf club head 100 according to Embodiment 1 includes a main body 10 and a hosel 20.

Main body 10 includes a toe 10 a, a heel 10 b, a top 10 c, a sole 10 d, a face 11, score lines (grooves) 12, a back face 13, a thin portion 14, a thick portion 15, and a cavity wall 16.

Face 11 and hosel 20 are made from the same material. The material for face 11 and hosel 20 is chromium molybdenum steel or nickel chromium molybdenum steel. The material for face 11 and hosel 20 is preferably nickel chromium molybdenum steel. While main body 10, except for face 11, of iron golf club head 100 according to Embodiment 1 is made from the same material as face 11, it may be made from a different material from face 11.

Face 11 and hosel 20 may be formed by casting, or formed by forging. For example, iron golf club head 100 according to Embodiment 1 has a one-piece cast structure.

Face 11 is a ball striking surface. Face 11 is surrounded by toe 10 a, heel 10 b, top 10 c, and sole 10 d. Toe 10 a is a part connecting top 10 c to sole 10 d on the side located away from hosel 20. Heel 10 b is a part extending from the lower end of hosel to sole 10 d Top 10 c is a part forming an upper edge of main body 10 extending from hosel 20 to toe 10 a. Sole 10 d is a part forming a lower edge (bottom) of main body 10.

Face 11 is provided with a plurality of score lines (grooves) 12. Each of a plurality of score lines (grooves) 12 extends linearly in the toe-to-heel direction from toe 10 a toward heel 10 b (direction laterally across face 11). A plurality of score lines (grooves) 12 are arranged at substantially regular intervals in the top-to-sole direction from top 10 c toward sole 10 d (direction vertically across face 11).

Back face 13 is located rearward of face 11. Back face 13 is located opposite to face 11. Back face 13 is provided to both thin portion 14 and thick portion 15.

As shown in FIGS. 2 and 3 , cavity wall 16 surrounds the perimeter of back face 13. Cavity wall 16 is formed to extend along toe 10 a, heel 10 b, top 10 c, and sole 10 d. Cavity wall 16 defines a cavity 17. Cavity 17 is surrounded by cavity wall 16.

As shown in FIG. 4 , thin portion 14 has a larger area than thick portion 15. In FIG. 4 , the region hatched by bold lines represents thin portion 14. Thin portion 14 has a larger area than thick portion 15 within the plane of back face 13. Thin portion 14 may have an area of 80% or more of the area of back face 13 as seen in plan view.

As shown in FIGS. 5 and 6 , thin portion 14 has a smaller thickness than thick portion 15 in the face-to-back direction from face 11 toward back face 13. Thin portion 14 has a smaller thickness than thick portion 15 in the face-to-back direction.

In the face-to-back direction, the thickness of thin portion 14 is 1.6 mm or more and 1.8 mm or less. In the case of thin portion 14 having a thickness of less than 1.5 mm, the upper limit of the coefficient of restitution rule of the R&A (Royal and Ancient Golf Club of St Andrews) may be exceeded. In the case of thin portion 14 having a thickness of 1.9 mm, a durability test is passed even if the hardness of face 11 is less than HV510, which, however, is accompanied by deterioration of the rebound property. Further, the weight of the face increases. Accordingly, the thickness of thin portion 14 has been set to 1.6 mm or more and 1.8 mm or less. The thickness of thin portion 14 is 1.7 mm, for example. The thickness of thin portion 14 may be substantially uniform. The thickness of thin portion 14 may also be uniform.

Thick portion 15 has a larger thickness than thin portion 14 in the face-to-back direction from face 11 toward back face 13. Thick portion 15 is larger in the thickness in the face-to-back direction than thin portion 14. The thickness of thick portion 15 is 2.0 mm, for example. This thickness of thick portion 15 is the maximum thickness of thick portion 15.

As shown in FIG. 4 , thick portion 15 is located centrally of back face 13, in the toe-to-heel direction from toe 10 a toward heel 10 b. Thick portion 15 is located to overlap the center of back face 13, in the toe-to-heel direction. Thick portion 15 is surrounded by thin portion 14. Thick portion 15, except for its portion facing sole is surrounded continuously by thin portion 14. As seen in plan view, thick portion 15 is formed substantially in the shape of an incomplete circle, i.e., a circular shape except for the portion facing sole 10 d.

As shown in FIGS. 5 and 6 , thick portion 15 protrudes from thin portion 14 in the face-to-back direction. On back face 13, thick portion 15 protrudes from thin portion 14 in the face-to-back direction. Thick portion 15 protrudes toward cavity 17 in the face-to-back direction.

As shown in FIGS. 4 and 5 , cavity wall 16 includes a sole-side wall 16 s. Sole-side wall 16 s is located on the sole 10 d side.

Thick portion 15 becomes narrower toward sole-side wall 16 s. The width, in the toe-to-heel direction, of thick portion 15 decreases toward sole-side wall 16 s. Thick portion 15 is contiguous to sole-side wall 16 s. Thin portion 14 is located between thick portion 15 and cavity wall 16 except for sole-side wall 16 s.

Sole-side wall 16 s includes a toe-side portion 16 a, a center portion 16 b, and a heel-side portion 16 c that are arranged in the toe-to-heel direction. Center portion 16 b is located between toe-side portion 16 a and heel-side portion 16 c in the toe-to-heel direction. Thick portion 15 is contiguous to center portion 16 b. Center portion 16 b has a larger thickness than toe-side portion 16 a and heel-side portion 16 c. The thickness of center portion 16 b is 1.9 mm, for example. The thickness of toe-side portion 16 a is 1.5 mm, for example. The thickness of heel-side portion 16 c is 1.5 mm, for example.

As shown in FIGS. 1 and 2 , a sweet spot of face 11 is located to overlap thick portion 15 in the face-to-back direction. The score-line center of face 11 is located to overlap thick portion 15 in the face-to-back direction.

Face 11 has a hardness of HV510 or more and HV600 or less. Namely, the hardness of face 11 is a Vickers hardness (HV) of 510 or more and a Vickers hardness (HV) of 600 or less. At and around the score-line center of face 11, face 11 has a hardness of HV510 or more and HV600 or less. In the case of face 11 having a hardness of less than HV510, face 11 subjected to a durability test based on ball hitting was identified as having cracks in face 11. The reason for the cracks was considered as the insufficient hardness of face 11. In the case of face 11 having a hardness of more than HV600, face 11 subjected to a durability test based on ball hitting was identified as having cracks in face 11. The reason for the cracks was considered as the toughness of face 11 that becomes lower as its hardness increases. Accordingly, the hardness of face 11 has been set to HV510 or more and HV600 or less. The hardness of face 11 herein refers to the hardness at and around the score-line center of face 11. The Vickers hardness is a value obtained by measuring the hardness of a site located at a distance of 1 mm from the face surface.

Hosel 20 is connected to heel 10 b of main body 10. Hosel 20 includes a region that is bent for adjusting the lie angle and the loft angle. Hosel 20 has a hardness of HV300 or less. Specifically, the hardness of hosel 20 is a Vickers hardness (HV) of 300 or less. In the case of hosel 20 having a hardness of HV300 or less, there is no inconvenience for a human to bend the hosel. Specifically, in the case of hosel 20 having a hardness of HV300 or less, a human operator can bend the hosel by a lie angle of 1 to 2 degrees for adjusting the angle. In the case of hosel 20 having a hardness of HV250 or less, the workability for adjusting the angle by a human operator is improved. In the case of hosel 20 having a hardness of more than HV300, it is difficult for a human to bend the hosel. Specifically, in the case of hosel 20 having a hardness of HV400, it is difficult for a human operator to bend the hosel by a lie angle of one degree for adjusting the angle. Accordingly, the hardness of hosel 20 has been set to HV300 or less. The hardness of hosel 20 herein refers to the hardness at a site located at distance of approximately 30 mm from the end of the hosel. The Vickers hardness is a value obtained by measuring the hardness at a site located at a distance of 2 mm away from the surface of hosel 20.

Referring to FIG. 7 , an iron golf club 200 according to Embodiment 1 is described.

As shown in FIG. 7 , iron golf club 200 according to Embodiment 1 includes iron golf club head 100 according to Embodiment 1, a shaft 201, and a grip 202.

Shaft 201 has one end and the other end. Iron golf club head 100 is attached to the one end of shaft 201. Shaft 201 is attached to hosel 20. The one end of shaft 201 is inserted in hosel 20. Grip 202 is attached to the other end of shaft 201. The other end of shaft 201 is inserted in grip 202.

Next, functions and advantageous effects of Embodiment 1 are described.

Regarding iron golf club head 100 according to Embodiment 1, the hardness of face 11 is HV510 or more and HV600 or less. Thus, face 11 can be made hard to suppress cracks of face 11 and improve the durability. Face 11 can therefore be designed to be thin, to thereby achieve both high rebound property and high durability. The hardness of hosel 20 is HV300 or less. Thus, the angle adjustment capability for adjusting the lie angle and the loft angle by deforming hosel 20 can be improved. Accordingly, both high rebound property and high durability can be achieved and the angle adjustment capability can also be improved.

Main body 10 includes thin portion 14 and thick portion 15. Thus, main body has a partially-thick structure. Thin portion 14 has a larger area than thick portion Thus, both high rebound property and high durability can be achieved with no or minimum increase of the mass of main body 10, as compared with main body 10 having no thin portion 14.

Thick portion 15 is located centrally of back face 13 in the toe-to-heel direction, and surrounded by thin portion 14. Thus, the difference in the total distance between the case where a ball is shot off-center and the case where the ball is shot at the sweet spot can be reduced, while the rigidity of the center of face 11 is improved.

Regarding iron golf club head 100 according to Embodiment 1, thin portion 14 has a thickness, in the face-to-back direction, of 1.6 mm or more and 1.8 mm or less. Thus, thin portion 14 can be made thin. It is therefore possible for thin portion 14 to deform easily when hit by a ball. Accordingly, high rebound property can be improved.

Regarding iron golf club head 100 according to Embodiment 1, thick portion 15 become narrower toward sole-side wall 16 s and is contiguous to sole-side wall 16 s. Thus, the area of thin portion 14 can be made larger, as compared with the case where thick portion 15 is not narrowed. Therefore, thin portion 14 can be deformed when hit by a ball, to improve the coefficient of restitution (COR). The coefficient of restitution (COR) of the toe side and the heel side can also be improved. Accordingly, high rebound property can be improved as well for the off-center shot where a ball is hit at the toe side or the heel side.

Regarding iron golf club head 100 according to Embodiment 1, center portion 16 b has a larger thickness than toe-side portion 16 a and heel-side portion 16 c. Thus, toe-side portion 16 a and heel-side portion 16 c can be deformed more easily relative to center portion 16 b. It is therefore possible to improve the coefficient of restitution (COR) of the toe side and the heel side. Accordingly, high rebound property can be improved as well for the off-center shot where a ball is hit at the toe side or the heel side.

Regarding iron golf club head 100 according to Embodiment 1, the material for main body 10 and hosel 20 is nickel chromium molybdenum steel. Thus, face 11 of main body 10 can be made harder to improve the durability, and face 11 can be designed to be thinner to improve high rebound property.

Iron golf club 200 according to Embodiment 1 includes iron golf club head 100 according to Embodiment 1. Thus, iron golf club 200 can be obtained that enables both high rebound property and high durability to be achieved, and the angle adjustment capability to be improved.

Embodiment 2

An iron golf club head 100 according to Embodiment 2 has the same configuration and the same functions and advantageous effects as iron golf club head 100 according to Embodiment 1, unless otherwise specified.

Referring to FIG. 8 , iron golf club head 100 according to Embodiment 2 is described. As shown in FIG. 8 , iron golf club head 100 according to Embodiment 2 differs from Embodiment 1, in terms of the configuration of thick portion 15.

In iron golf club head 100 according to Embodiment 2, thick portion 15 extends straight toward sole-side wall 16 s. That is, thick portion 15 is not narrowed toward sole-side wall 16 s.

Iron golf club head 100 according to Embodiment 2 also enables both high rebound property and high durability to be achieved, and the angle adjustment property to be improved.

Embodiment 3

An iron golf club head 100 according to Embodiment 3 has the same configuration and the same functions and advantageous effects as iron golf club head 100 according to Embodiment 1, unless otherwise specified.

Next, referring to FIGS. 9 to 14 , iron golf club head 100 according to Embodiment 3 is described. As shown in FIGS. 9 to 14 , iron golf club head 100 according to Embodiment 3 differs from Embodiment 1 in terms of the configuration of thick portion 15. In FIG. 12 , the region hatched by bold lines represents thin portion 14.

As shown in FIGS. 9 to 12 , in iron golf club head 100 according to Embodiment 3, thick portion 15 includes a first portion 151, a second portion 152, and a third portion 153. First portion 151 is located between second portion 152 and third portion 153 in the toe-to heel direction. As seen in plan view, first portion 151 is formed substantially in the shape of an incomplete circle, i.e., a circular shape except for the portion facing sole 10 d.

Second portion 152 protrudes from first portion 151 toward toe 10 a. As seen in plan view, second portion 152 is formed substantially in an oval shape, except for the portion connected to first portion 151. Second portion 152, except for the portion connected to first portion 151, is surrounded continuously by thin portion 14. Second portion 152 is located centrally of back face 13 in the top-to-sole direction. In the top-to-sole direction, thin portion 14 is located on the top side and the sole side of second portion 152. Second portion 152 is located to overlap the height position of a sweet spot in the top-to-sole direction.

Third portion 153 protrudes from first portion 151 toward heel 10 b. As seen in plan view, third portion 153 is formed substantially in an oval shape, except for the portion connected to first portion 151. Third portion 153, except for the portion connected to first portion 151, is surrounded continuously by thin portion 14. Third portion 153 is located centrally of back face 13 in the top-to-sole direction. In the top-to-sole direction, thin portion 14 is located on the top side and the sole side of third portion 153. Third portion 153 is located to overlap the height position of the sweet spot in the top-to-sole direction.

As shown in FIGS. 13 and 14 , second portion 152 has a smaller thickness than first portion 151 in the face-to-back direction. The thickness of second portion 152 in the face-to-back direction is 1.85 mm, for example. This thickness of second portion 152 is the maximum thickness of second portion 152.

Third portion 153 has a smaller thickness than second portion 152 in the face-to-back direction. The thickness, in the face-to-back direction, of third portion 153 is 1.8 mm, for example. This thickness of third portion 153 is the maximum thickness of third portion 153.

In iron golf club head 100 according to Embodiment 3, thick portion 15 includes first portion 151, second portion 152 protruding from first portion 151 toward toe 10 a, and third portion 153 protruding from first portion 151 toward heel 10 b. Thus, the difference in the total distance between the case where a ball is hit at the toe side or the heel side, i.e., off-center shot, and the case where the ball is hit at the sweet spot, can be reduced, while the rigidity of the center of face 11 is improved.

Second portion 152 has a smaller thickness than first portion 151 in the face-to-back direction, and third portion 153 has a smaller thickness than second portion 152 in the face-to-back direction. The coefficient of restitution (COR) of the toe side and the heel side can be improved. Thus, high rebound property can also be improved for the off-center shot where a ball is hit on the toe side or the heel side, while the rigidity of the center of face 11 is improved.

Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the scope of the present invention being interpreted by the terms of the appended claims. 

What is claimed is:
 1. An iron golf club head comprising: a main body including a toe, a heel, a face, and a back face; and a hosel connected to the heel of the main body, wherein the face and the hosel are made from the same material, the face includes a thin portion and a thick portion having a larger thickness than the thin portion in a face-to-back direction from the face toward the back face, the thin portion has a larger area than the thick portion, the thick portion is located centrally of the back face in a toe-to-heel direction from the toe toward the heel, surrounded by the thin portion, and protrudes from the thin portion in the face-to-back direction, the face has a hardness of HV510 or more and HV600 or less, and the hosel has a hardness of HV300 or less.
 2. The iron golf club head according to claim 1, wherein the thin portion has a thickness of 1.6 mm or more and 1.8 mm or less in the face-to-back direction.
 3. The iron golf club head according to claim 1, wherein the main body includes a cavity wall surrounding a perimeter of the back face, the cavity wall includes a sole-side wall, and the thick portion becomes narrower toward the sole-side wall and is contiguous to the sole-side wall.
 4. The iron golf club head according to claim 3, wherein the sole-side wall includes a toe-side portion, a center portion, and a heel-side portion that are arranged in the toe-to-heel direction, and the center portion has a larger thickness than the toe-side portion and the heel-side portion.
 5. The iron golf club head according to claim 4, wherein the thick portion includes a first portion, a second portion protruding from the first portion toward the toe, and a third portion protruding from the first portion toward the heel, the second portion has a smaller thickness than the first portion in the face-to-back direction, and the third portion has a smaller thickness than the second portion in the face-to-back direction.
 6. An iron golf club comprising: the iron golf club head according to claim 1; and a shaft attached to the hosel. 